In recent years, as the Internet and digital contents such as so-called compact discs and digital video discs are becoming common, problems of which the digital contents are illegally copied and the copyrights thereof are infringed have taken place.
From a view point of the protection of the copyright, to deal with a problem of copyright infringement, copyright information such as copyright control information is added to digital contents. It can be considered that with the additional information, digital contents are prevented from being illegally copied. Among illegal copy protecting technologies, an electronic watermark technology is becoming attractive because it is difficult to illegally forge additional information.
An electronic watermark process is a process for embedding additional information as noise to a perceptually unimportant portion of image data and music data (namely, a redundant portion of image data and music data).
It is difficult to remove the additional information that has been embedded in image data and music data by such an electronic watermark process. On the other hand, after a filtering process and a data compressing process have been performed for image data and music data, it is possible to detect the embedded additional information from the image data and music data.
Thus, it can be expected that the copyright of content data can be effectively protected in such a manner that copyright information such as copy generation restriction information as additional information of an electronic watermark (hereinafter, the additional information of the electronic watermark is referred to as electronic watermark information) is embedded in content data, the resultant content data is transmitted, and the copyright information is used for controlling a copying operation.
However, a detector that detects electronic watermark information is relatively expensive. Thus, when a detector that detects such electronic watermark information is used for an outputting apparatus, a reproducing apparatus, and a recording apparatus, from a view point of the manufactures thereof, their costs rise. Thus, when a system that causes the users to actively use the detectors is not assured, unless there is a legal restriction against the use of such a detector, it is difficult to force the manufactures to dispose the detectors in the apparatuses.
Likewise, when additional information such as advertise information is added to content data, a system that causes the users to actively use the additional information is important.
From a forgoing point of view, an object of the present invention is to provide a data outputting method, a data reproducing method, a data recording method, and their apparatuses, and a record medium that are suitable for a system that causes users to actively use additional data such as electronic watermark information and advertisement information of content data.